As we said earlier this is one of several developing stories. Now to new details emerging on the train crash right in the middle of friday rush hour. Two packed commuter trains colliding outside new york city. 70 people hurt. Some of them critically. Federal investigators now heading to the scene in bridgeport, connecticut, and that is where we find abc's marci gonzalez. Good morning to you, marci. Reporter: Good morning, dan. This morning dozens of those passengers remain hospitalized. At least three in critical condition. And the ntsb will be here on the scene today trying to figure out how this happened. All of a sudden we hear, boom and then we saw like smoke everywhere. Reporter: A terrifying collision, a commuter train derailing, smashing into another. We heard something and the train rolled sideways. Reporter: It happened just after 6:00 last night during the busy evening rush. A metro north train leaving new york city somehow losing control here near bridgeport, connecticut, barreling straight into the path of another train heading in its direction. Between the two, 700 people were on board. My immediate instinct was to get up and brace myself because I could see that we were going towards whatever derailment had happened. Reporter: But others were not as fortunate. At least 70 people were injured. Passengers helped passengers off the trains and into the care of first responders. It was kind of in and out of consciousness, kept asking the same question over again. What happened. Where are we? I kept telling her we were on the train. It crashed. Reporter: The wreckage still on the tracks this morning. Evidence of how fierce the impact was as those who walked away from the twisted railcars say it could have been so much worse. I think had we been going faster I think there would have been a lot more destruction. Reporter: And these same tracks are used by amtrak and now service from new york to boston is canceled until the wreckage can be cleared. Still no word on how long that could take. Bianna? Busy weekend for the ntsb investigating two potentially fatal incidents. All right, marci, thank you so much.

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